Method of recording musical tones.



G. F. STODDARD.

,1 908. RENEWED AUG. 28,1913.

Patented Apr. 28, 1914.

druzs es h [7206 Z01:- cgagnh'fi f{-v/ Charles Sladdard. ce l6 by various embodiments of which UNITED STATES PATENT OFFICE.

CHARLES F; STODDARD, OF BOSTON, MASSACHUSETTS.

METHOD OF RECORDING MUSICAL TONES.

Application filed April 30, 1908, Serial No. 430.082.

' Be it known that 1, CHARLES F. Brennan, a citizen of the United States, residing at Boston, in the county of Suffolk, Commonwealth of l'lassachusctts, Improvement in Methods of Recording Musical 'l'cnes, of which the following description, in connectionwith the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention relates to a method of recording a musical tone or group of tones; and as'herein described it pertains more particularly to a method of recordin one or more characteristics of tones played upon a piano,

For purposes of illustration the invention may be described herein in connection with a preferred method and product which respectively may be practised and produced conveniently by means of mechanism shown in the accompanying drawings, in which;

Figure l is a diagrammatic side elevation partly in section, of a detached key action and one practicable illustrative .form of recording means; Fig. 2, a detail view similar to that of Fig. 1, showing a key action at the moment of sounding a tone; Fig. 3, a view similar to Fig. 2, showing the kc action-after a string has been struck and while it is still sounding; Fig. 4, a detail section on the line -t--at of Fig. 1; Figs. 5. 6 and 7, diagrammatic views, showing different positions of illustrative key-controlled means for governing the recorder; and Figs. 8 and 9 illustrate, respectively, forms of records embmlying this invention.

It. is to be understood, of course, that neither a method nor a product, embodying features of this invention, is to be limited to the apparatus shown in the accompanying drawings, nor to the specific methods and records herein described to exemplify the the invention is susceptible.

For present purposes, an individual musical tone. may be said to have three prineipal charaeteristics,-pitch, intensity and duration. The different tones of a group or series have time relations, usually designated the tempo' of a musical production.

it is an object of this invention, inter alin, to provide a method of representing sensibly, as for recording purposes, one or more of the above suggested characteristics or qualities.

have invented an Specification of Letters Patent.

Patented Apr. 8, 1914. Renewed August 2s. 1913. Serial No. 787,204.

For convenience ferred method will tion with and 4.

Fig. 1 shows a typical key action in its normal position of rest, When the key A is st ruck it elevates a sticker B, rocking a han'uner (l and causing the latter to strike-a string l), at the same time withdrawing from the string a damper E. The striking position of the hammer C and the corresponding position of the damper E are shown insFig. 2. So long as the key A is held depressed by the performer, after striking the tone, the parts will remain in the position of Fig. 3, the damper E being removed from the strin and the hammer C standing intermediate its striking position and its position of rest. This mode of behavior of a piano action may be utilized conveniently in recording characteristics of the tone produced.

The amplitndeof sound waves propagated by vibrationof the string D defines the intensity of the tone, and depends upon the violence with which the hammer C strikes the string-that is to say, depends upon the dynamic force with which the string is struck. This force, according to fundamental principles, depends upon the mass of the hammer (l and its velocity upon striking the string. he mass is a. constant for each of the hammer actions in a piano. The velocity involv es the two elements of distance and time, the distance through which the hammer moves during its striking travel, and the time consumed in making this movement. As hereinafter described, it is preferred to employ only a part of this travel of the hammer for recording purposes; but. since the same length of travel is preferably always used, the distance element may be considered also a constant. Thus the time interval of hammer travel may be the only variable involved in variations of tone intensity. For any tone, therefore, this time interval supplies a convenient inverse measureof its intensity. To illustrate the present invention, a method will be described wliieh'employs this time measure in representing intensities.

The duration of the usual tone depends upon the period of time after the string is struck, during which the damper E is held away from the string; the'tone beginning when the hammer strikes the string and the apparatus of Figs. 1, 2, 3

ending when the damper is returned to damp the vibration of the string. Thus a second time element atlords a convenient measure for tone duration; and this measure is employed for illustration in the exemplary method described herein. The pitch of a tone depends upon which string is struck, and the illustrative method about to be described differentiates between tones of different pitches by suitably relating the records of the respective tones. The tempo of a composition depends upon the time relations of the diiferent tone-sounding operations; and according topthe illustrative method, the recording of 3 the latter in proper relations serves also to record the tempo. 7 I

Referring again to Fig. 1, the hammer C has rigidly mounted upon it integral electrical contact points 10 and 11, arranged respectively to enter mercury baths 12 and 13.

The mercury 12 is electrically connected throu h a battery 14, with a line 15 to a recor ing device;and the mercury bath 13 is electrically connected to the recording device by a line 16. When the piano action is at rest, as in Fig. 1,.the' contact point ll stands above ithesurface ofthe mercury bath 13 and the circuit is broken, the contact point 10 being then deeplyimmersed in the bath 12. When the key rocks from the po. sit-ion in Fig. 1, toward that of Fig. 2, and preferably at some point during the latter part of the striking movement, the contact point 11 enters the mercury bath-13 and completes the circuit from the battery through the recording means, the mercury baths and the contact points 10 and 11. The closing of this circuit actuates the recording means to initiate a record. At the moment the hammer C strikes its string the contact point 10 iswithdrawn from the mercury bath 12, and the circuit is again broken and the recording means rendered inactive to terminate its initial record. With this mode of operation, a. record continues during preferably the latter part of the travel of the hammer to strike a string, when it has attained its full working velocity; and the time consumed duringsuch travel may be indicated by the record, to represent the intensity of the tone. If the hammer accomplish the given travel in quick time-4. e. with a relatively great velocitya loud tone results, as indicated by a short time record; if the hammer travel consumes more timei. e. havingless veloci ya tone of less in tensity will be'sounded and this will be indicated by a longer time record.

A conve ient form of record: lending itself rcadi y to the accurate ascertainment of represented intensities, consists of, a straight line, the length of which may indicate by its linear units the interval of time ensuing between the first recorded position of the hammer and the final striking position. Thus a long line would indicate a slow moving hammer and a relatively soft tone; while a shorter line would indicate a swiftlymoving hammer and a louder tone. Figs. 1 and 4 illustrate recording means capable of making such a record as has just been suggested. This mechanism comprises a platen roll 20 which may have its surface covered with an imprinting medium such as Elyof record receiving carbon aper. A su materia R, such as 5 sheet of paper, may be woundupon a drum? 2, passing thence over the platen 20 and beneath a feeding drum 24 and between the latter and a friction idler 26. The feeding drum 24b may be rotated in any practicable manner, as by avworm and gear illustrated invFig. 1. A constant speed of movement of the record receivin material R is best for the purposes of the specific apparatus shown.

The inner. face of the record sheet R, lying next the platen 20, contacts with the carbon paper thereon and receives the rec- 0rd. A stylus 28 rests normally upon the record sheet R on the opposite side thereof from the carbon-paper. An armature 30 of an electromagnet-rests with its dead weight upon the upper end of the stylus 28. The combined weights ofthe stylus and armature are not sufiicient to press the record sheet R 'againstthe carbon so as to make a mark thereon; but when said armature is magnetically actuated to add pressure to the-stylus 28 the latter,'by its pointed end, presses the recording sheetR against the carbon and causes a mark to be made upon the sheet so long as the magnetic actuation of the armature continues.

The armature 30 is operated by an electromagnet 32 which is. in circuit with the lines 15 and 16 and battery 14. Thus, so long asthe circuit remains closed by the contact points 10, 11 being simultaneously im- 'mersed in their mercury baths, the magnet 32 will be energized, and the armature 30 attracted to depress the stylus 28, causing a mark to be recorded upon the record sheet R.

Each key acg'ion of a piano may be. connected in the manner described with a mag- I net, to act upon its individual armature for depressing its individual stylus, feach independently ofihe others; and for illustration a plurality of magnets 32 and 33 and armatures 30 and 34 are shown, conveniently 1 banked and nested, in Figs. 1 and 4, which show also the appropriate Styli 28,35 and 3G. W'ith the arrangement'des'cribed the first recorded point in the travel of a hammer C is preferably always the same and may be advantageously the position of the hammer at the time when the damper leaves the string. the hammer having then acquired substantially its maximum working velocity. The time interval consumed in the hannncr travel is arcuratelyrecorded by the length of line made upon the record sheetbetween the first record point when the magnet is energized by closing the .circuit, and the last recorded point preferably as the hammer strikes its string, at which the line ends upon breaking of the circuit.

The time interval of hammer travel may be measured in standard units of time by means of a suitable chronograph or the like. Comparison of such measurement with the corresponding recorded line will yield a linear unit accurately representative of a standard unit of time. lVith such a unit of measure the exact time represented b any recorded line may be ascertained, as in seconds. Also, the distance of hammer travel and the mass of the hammer can be readily measured. Having ascertained these constants, it is possible to ascertain the variable time factor for any tone instandard units by reference to the record; and by combining the two constant factors with the variable so determined, the exact force with which a string is struck may be calculated with mathema ical accuracy. This process yields in terms of units of force, a force which maybe used to reproduce with fidelity the touch any particular tone.

While the extreme, accuracy accessible as just described in the practice of a method embodying this invention, may be desirable in some' cases, it suflices for usual commercial practices to represent merely the relative intensities of different tones of a performance, regardless 0f the absolute units of intensity. or factorsdetermining intensity. It is practicable, '1 terefore, to adopt an arbitrary grading of intensities such that all tones approximating certain intensities shall; be classed in one grade; these approximating another intensity shall be clas ed in an other grade; and so on. Thus gsing the specific illustrative record deschbed, all recorded intensity lines approximating an arbitrary selected length may be graded as having an intensity equal to m; those being recorded with lines approximating another length may be graded as having an intensity of y,- and so on. Thus, in re producing intensities recorded as heretofore described, tones having recorded intensity lines of one class may be given all the same appropriate intensity.

Referring now to Fig. 8there is shown a record such as may be made with the devices and by the method already described for illustration. The fragmentary record sheet there shown is assumed to be traveling toward the left. the left hand part of the sheet showing the initial record lines. The line 50 is started at the moment the electrical contaet l1 enters its mercury bath and closes the circuit through the recording de' employed in producing vice;'and this line continues until the electrical contact 10 emerges from its bath preferably at the instant the hammer C strikes the string. Thus the line 50 supplies a record of the time consumed by the hammer in traveling over its appointed distance; and therefore said line affords the convenient representation of intensity hereinbefore referred to. In like manner, the lines 51, 52, 53, 54 and 55 indicate the time of travel of other hammers in sounding other tones. For instance, the line 55 being very short indicates rapid travel of the hammer, and therefore a loud tone. For convenience in illustration, the various intensity record lines in Fig. 8, are graded from line 50, indicating the softest tone, to line 55, indicating the loudest.

When the string is struck the hammer C at once rebounds from the positionof Fig. 2 to the position of Fig. 3, a short, interval intervening between the withdrawal of the contact point 10 from its bath and its reinsertion therein upon the rebound of the hammer. This interval causes an interruption in the magnetic action on the recording stylus and leaves a gap 56 in the record. When, however, the hammer again closes the circuit the record line begins again and endures preferably until the damper E arrests the vibration of the string, as when the piano-key is released, permitting the hammer action to resume the position shown in Fig. 1. In returning to this position, the contact point 11 is removed from its mercury bath and.the record ceases. Thus, in' addition to the line 50, the record of any; given tone may comprise also a line 57, the right hand end of the latter in Fig. 8 indicating the end of a. note. It will be remembered that the right hand end of a line 50 prefer- .ably indicates the instant at which the ham mer C strikes the string, and initiates the sounding of a tone. Accordingly, the distance intervening between the right hand end of line 50 and the right. hand end of a line 57 serves as a convenient measure or record of the duration of the tone.

As Wlll be readily understood by those familiar with the ark-the individual time values of the notes being indicated as just described; and the tones being recorded in proper sequence as they are played, by reason of the records being made immediately in response to the playing of the respective tones, the tempo of a composition is clearly indicated by the relations of the different lines appearing on the record, as in Fig. 8. The pitches of the different tones are also readily asccrtainahle by comparing the records with a keyboard; or by employing a suitable scale. provided if desired on the record sheet itself. Thus from a single record, such as is shown in Fig. 8, the characteristics of an individual tone or group of rcsponds'to the line 16 of Fig. 1; and the spring 61.

Contact spring (32 has connected to it a wire 65, corresponding to the line 15 of Fig. 1, a battery being introduced into circuit with said wires and a recording device.

\Vhen the key At stands in its normal inactive position shown in Fig. 5 the contact controller 60' holds the spring 61 'out of contact with the connector 63 and thereby holds the recording circuit broken. 'When, however, the key is depressed-to produce a t ne,-at some time during the travel of the key, preferably during the latter part,

the spring 61 contacts with the conneetor 63 I and completes the circuit to initiate a record as already described, thereby starting a line shown in Fig; 9. Upon further'depression of the key 1' (see Fig. 7) the contact controller 60 strikes the spring (32 and again breaks the circuit and arrests the recording operation, thereby terminating the line 70. Thus the line 70 may serve. as a record of the' time consumed by the. movement of the key action betweenpredetermined pointsthis time record-serving as'already suggested as a convenient representation of the intensity of the tone.

The right hand end of the line 70 in Fig. 9 may represent. approximately the time of striking the string. So long as the key is held depressed by the player the circuit re- .mains broken; and during this time the tone continues to sound. Then the key is released and the contact controller 30 moves upwardly the spring (-2 contacts with the connector 63 and closes the circuit to initiate a line 71: and therea tter the key ascends to its normal inactive position and lifts the again breaking tbecircuit and terminating'tbe line I1. Thus the left hand end of the line 71' may indicate approximately the end of the tone and the duration otflle tone is indicated by the distance betivei-ii the right hand end of the line 70 and lett-hand end of tbcline 71.

dicate'tcmpo and pitch, as already described.

In like manher the lines 80 and S1 nnrvmdrcate singly The preceding description and explanation will sutlice to suggest the various embodiments of which the invention is susceptible. It is to'be understood, of course, that the invention is not limited to the specific disclosure hereinbefore made: on the contrary, as will appear to those skilled in the art, the specific methods and articles described for illustration may be variously changed and modified without departing from the proper scope of the subjoined claims.

" Claims.

1. method ht making readable records indicative of the'inteusllies of tones produced by a stringed musical instrumcnh which comprises recording upon a uniformly moving record-receiving sheet a plurality of parallel straight lines. one line for each tone to be recorded, each said line beginning at substantially the instant'ot undamping its corresponding string and terminating at substantially the instant of striking said string, whereby the length of each line so recorded graphically represents the elapsed time'between the undamping and the 'strile ing of the corresponding string.-

2. A method otmaking readable records indicative of the intensities of tones pro- ;duced by a stringed musical instrun'ient.

which comprises. recording upon a uniformly moving record-receiving sheet a pinrality of parallel straight lines, one line for mat tone to be recorded, said linesbeginning at the samestages in the operations of their respective tone-sounding actions prior to the sounding of the respective tones,- and each said line terminating at substantially the time at which its'corresponding string is struclc;whereby the length of each said line graphically repre ents the elapsed time hetucen the lirst said stage and substantially the time of striking the slringf I). method of making readable records indicative of the intensities of tones produced by a stringed musical instrument, which comprises recording upon a recordra-ceiving slicet \\-'hich moves uniformly in relation to cooperating recording means, a plurality of parallel lines. one line for each tone to he recorded. said lines being 80 recorded during equal movenwnts of their re.-

spective tone-sounding actions. and each said indicative of the intensities of tones produccd by a stringed musical instrument, which comprises recording in. rectilinear alineincat' and along a record-receiving'medium which movcsunitorinlyn'n relationrto cooperating recording means, a plurality of selected successive stages in the operation of a tone-sounding action, including, first, a stage prior to the sounding of the tone, and, second, substantially the stage when the sound begins, whereby the linear distance between the records of sa d stages represents the elapsed time between said stages of operation.

5. A method of making readable records indicative of the intensities of tones produced by a stringed musical instrument, which comprises recording in rectilinear alinement along a record-receiving medium, a plurality of selected successive stages in the operation of a tone-sounding action, including, first, a stage prior to the sounding of the tone, and, second, a subsequent stage not late* than that at which the sound hegins, whereby the linear distance between the records of said stages represents the elapsed time between said stages of operation. I

6. A method of making readable records indicative of the intensities of tones pro duced by a stringed musical instrument, which comprises recording, for each of a plurality of tones, in rectilinear alinement for each tone, the alinements for different tones-being parallel, a plurality of selected successive stages in the operation of atonesounding action, including, first, a stage prior to the sounding of the tone, and, second, a subsequent stage not later than that at which the sound begins, whereby the liliear distances between the first and second records for the respective tones, said distances being measured along parallel lines, represent respectively in inverse proportion,

the relative speeds of the tone sounding actions.

7. A method of making readable records indicative of the intensities and durations of tones produced by a stringed musical in strument, which comprises recording in rectilinear alinement along a record-receiving medium, a plurality of selected successive stages in the operation of a tone-sounding action, including, first, the undamping of the string preparatory to sounding the same, second, substantially the striking of the string, and, third, the damping of the string to terminate the sounding of the tone.

8 A method of making readable records which the sound ceases, the records of said three stages for each tone being alined and in parallelism to the corresponding records for the other tones.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

CHARLES F. STODDARD. \Vitnesses PAUL DUDLEY DEAN, RonEIrr H. KAMMLER, 

